原文  http://blog.csdn.net/phantomes/article/details/26570113

/** JQuery Html Encoding、Decoding 
* 原理是利用JQuery自帶的html()和text()函式可以轉義Html字元 
* 虛擬一個Div通過賦值和取值來得到想要的Html編碼或者解碼 
*/  
<script src="http://libs.baidu.com/jquery/1.9.0/jquery.js"></script>  
<script type="text/javascript">  
//Html編碼獲取Html轉義實體  
function htmlEncode(value){  
  return $('<div/>').text(value).html();  
}  
//Html解碼獲取Html實體  
function htmlDecode(value){  
  return $('<div/>').html(value).text();  
}  
</script> 
 

<script type="text/javascript">  
//獲取Html轉義字元  
function htmlEncode( html ) {  
  return document.createElement( 'a' ).appendChild(   
         document.createTextNode( html ) ).parentNode.innerHTML;  
};  
//獲取Html   
function htmlDecode( html ) {  
  var a = document.createElement( 'a' ); a.innerHTML = html;  
  return a.textContent;  
};  
</script>

//編碼  
  function html_encode(str)  
  {  
      var s = "";  
      if (str.length == 0) return "";  
      s = str.replace(/&/g, ">");  
      s = s.replace(/</g, "<");  
      s = s.replace(/>/g, ">");  
      s = s.replace(/ /g, " ");  
      s = s.replace(/\'/g, "'");  
      s = s.replace(/\"/g, """);  
      s = s.replace(/\n/g, "<br>");  
      return s;  
  }  
  
  //解碼  
  function html_decode(str)  
  {  
      var s = "";  
      if (str.length == 0) return "";  
      s = str.replace(/>/g, "&");  
      s = s.replace(/</g, "<");  
      s = s.replace(/>/g, ">");  
      s = s.replace(/ /g, " ");  
      s = s.replace(/'/g, "\'");  
      s = s.replace(/"/g, "\"");  
      s = s.replace(/<br>/g, "\n");  
      return s;  
  }